Metabolic profiling

Metabolic interactions between the gut microbiome and its human host are thought to play a key role in the development of IBD and may hold the key to finding new disease markers and targets for intervention.

Professor Stefan Schreiber (Germany) reviews his presentation on the potential of metabolic profiling in IBD.

Professor Stefan Schreiber (University Hospital Schleswig-Holstein, Kiel, Germany) presented the potential of microbiome research to unlock important insights into the causes of IBD and provide markers and therapeutic targets for intervention. Metabolomic profiling of the human microbiome has identified a range of disturbed metabolic pathways and reduced microbiome-host metabolic cooperativity in IBD patients that could potentially be used to diagnose and classify IBD with greater accuracy than generic markers of epithelial inflammation.

One such marker is the amino acid tryptophan which is produced and consumed by bacteria in the gut microbiome and which is instrumental in maintaining immune homeostasis and epithelial barrier function in the gut. IBD patients have decreased serum levels of tryptophan; tracer studies have shown that this is due to increased consumption of tryptophan by the microbiome rather than impaired uptake. Serum tryptophan levels have been shown to correlate with disease activity in IBD and could also predict the need for surgery.

In a recent proof-of-concept study nicotinamide was administered in a pH-sensitive microcapsule formulation in an attempt to achieve targeted ileocolonic release; using this formulation, high doses of nicotinamide could be delivered to the target area and resulted in a significant increase in the abundance of Bacteroidetes species. Another feature of the gut microbiome that has been linked with IBD is the level of disorganisation of microbial communities and the loss of crosstalk between the host and the microbiome. The German Twin Study has shown a negative correlation between bacterial phyla and host transcripts in individuals who develop disease compared with healthy individuals. In patients who respond to treatment and achieve remission this metabolic cooperativity is restored, which supports the hypothesis that the metabolic functions of the gut microbiome may offer targets for interventions to treat IBD in the near future.

Based on presentations at the 14th Congress of ECCO, 6–9 March 2019, Copenhagen, Denmark.